Multi-excitation-source axial-flux permanent-magnet motor with partitioned, hierarchical, and variable poles, and variable-condition driving control system

Abstract

The present disclosure provides a multi-excitation-source axial-flux permanent-magnet motor with partitioned, hierarchical, and variable poles, and a variable-condition driving control system. The motor mainly includes a main magnetic pole and an auxiliary magnetic pole. The main magnetic pole is responsible for providing a main air gap flux and is connected in series with a dual-stator magnetic circuit. The auxiliary magnetic pole is responsible for adjusting an air gap field and is connected in parallel with the dual-stator magnetic circuit. Magnetic fluxes of the main magnetic pole and the auxiliary magnetic pole together constitute the air gap field. The present disclosure can control a flux path of the auxiliary magnetic pole by controlling the magnitude of a current applied to a field winding, thereby adjusting an air gap flux, expanding a speed range of the motor, and achieving variable-condition operation of the motor.

What is claimed is: 
     
       1. A logging method based on a time-domain electromagnetic tensor, wherein the method comprising: A multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor, comprising a first stator, a second stator, a first permanent magnet, a second permanent magnet, a third permanent magnet, a fourth permanent magnet, a first rotor yoke, a second rotor yoke, a first armature winding, a second armature winding, a first field winding, a second field winding, a first air gap, and a second air gap, wherein the first stator and the second stator are symmetrically provided outside the motor, with respective slots facing inward; the first armature winding is wound on stator teeth of the first stator in a distributed structure; the second armature winding is wound on stator teeth of the second stator in a distributed structure; the first field winding is wound on the stator teeth of the first stator in a centralized structure; the second field winding is wound on the stator teeth of the second stator in a centralized structure; the first rotor yoke and the second rotor yoke are symmetrically provided inside the motor, with respective slots facing inward; a plurality of fan-shaped slots are uniformly distributed inside the first rotor yoke and each are provided therein with the third permanent magnet; a plurality of fan-shaped slots are uniformly distributed inside the second rotor yoke and each are provided therein with the fourth permanent magnet; positions of the fan-shaped slots on the first rotor yoke and the second rotor yoke are completely symmetrical; the first permanent magnet and the second permanent magnet are provided between the first rotor yoke and the second rotor yoke; the first permanent magnet and the second permanent magnet are spaced apart from each other and circumferentially staggered from the third permanent magnet and the fourth permanent magnet; the first air gap is provided between an inner side of the first stator and an outer side of the first rotor yoke; the second air gap is provided between an inner side of the second stator and an outer side of the second rotor yoke; and an axis of the first stator and the second stator coincides with a rotational axis of the first rotor yoke and the second rotor yoke. 
     
     
       2. The multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , wherein the first stator and the second stator each comprise a stator core formed by winding a silicon steel sheet circumferentially and the stator teeth formed in a part facing a rotor; the first rotor yoke and the second rotor yoke each comprise a rotor core formed by winding a silicon steel sheet circumferentially; and in a design of the multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor with high-speed operation, the rotor core of the first rotor yoke and the rotor core of the second rotor yoke are die-cast from a soft magnetic material. 
     
     
       3. The multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , wherein the first armature winding and the second armature winding are double-layer windings of a distributed structure, with a pitch of ≥360°/(2*p), wherein p denotes a number of rotor pole pairs;
 the first field winding and the second field winding are single-layer windings with an interval of 120°*Z/(2*p), wherein Z denotes a number of stator slots; and 
 8 of the fan-shaped slots with a depth of 3 mm and a curvature of 0.285*360°/(2*p) are uniformly distributed inside the first rotor yoke, with a spacing of (1−0.285)*360°/(2*p) between each two adjacent ones of the fan-shaped slots; and 8 of the fan-shaped slots with a depth of 3 mm and a curvature of 0.285*360°/(2*p) are uniformly distributed inside the second rotor yoke, with a spacing of (1−0.285)*360°/(2*p) between each two adjacent ones of the fan-shaped slots. 
 
     
     
       4. The multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , wherein the first permanent magnet and the second permanent magnet each comprise p pole pairs distributed circumferentially and alternately in N and S; the first permanent magnet and the second permanent magnet are magnetized in opposite directions along an axial direction of the motor; the third permanent magnet and the fourth permanent magnet are magnetized in opposite directions along a tangential direction of the motor; a magnetic energy product of the first permanent magnet and the second permanent magnet is greater than a magnetic energy product of the third permanent magnet and the fourth permanent magnet; and the first permanent magnet and the second permanent magnet are spaced 0.55*360°/(2*p) apart and circumferentially staggered by 0.1325*360°/(2*p) from the third permanent magnet and the fourth permanent magnet; and
 a magnetic flux generated by the third permanent magnet and the fourth permanent magnet basically does not participate in an excitation of an air gap field in an unloaded state and participates in the excitation of the air gap field in a loaded state, thereby changing a magnetic flux of a main magnetic circuit of the motor and expanding a speed range of the motor; and when the third permanent magnet and the fourth permanent magnet are made of a ductile alnico material, a direct current excitation is applied through the first field winding or the second field winding to adjust the magnetic energy product of the third permanent magnet and the fourth permanent magnet. 
 
     
     
       5. The multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , wherein a hollow heat dissipation hole is provided between rotor cores of the first rotor yoke and the second rotor yoke to reduce a rotor temperature and a risk of permanent magnet demagnetization by means of oil cooling and air cooling; and an arc-shaped groove with a depth of H≤3 mm is provided at a position axially opposite to the first permanent magnet and the second permanent magnet at an air gap side of the first rotor yoke and the second rotor yoke, to adjust a magnetic flux of the first permanent magnet, the second permanent magnet, the third permanent magnet, and the fourth permanent magnet, and to reduce a cogging torque and an axial magnetic pull of the motor. 
     
     
       6. The multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , wherein when the first field winding and the second field winding fail, the first armature winding and the second armature winding operate independently without affecting normal operation of the motor; and when the first armature winding and the second armature winding fail, the first field winding and the second field winding replace the first armature winding and the second armature winding and are energized with a three-phase current to drive the motor to operate, thereby improving fault tolerance and operational reliability of the motor. 
     
     
       7. The multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , wherein the first stator and the second stator are staggered by a predetermined angle of α≤120° *Z/(2*p); and the angle is controllable to change a leakage flux and an air gap flux density of the motor, thereby changing an output torque and a power level of the motor, wherein p denotes a number of rotor pole pairs and Z denotes a number of stator slots. 
     
     
       8. A variable-condition driving control system of the multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 1 , comprising a motor power converter composed of four H-bridges, wherein inlet and outlet terminals of the first field winding and the second field winding are respectively connected to center points of the H-bridges, and inlet and outlet terminals of the two armature windings on the first stator and the second stator are respectively connected to the center points of the H-bridges to form an open winding structure or a dual-three-phase structure; and the H-bridges of the first field winding and the second field winding are connected in series with an open winding structure busbar of three-phase windings. 
     
     
       9. The variable-condition driving control system of the multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 8 , wherein a number of the three-phase windings is two, multi-mode operation is achieved; when neutral points of the two three-phase windings on the first stator and the second stator are disconnected, the motor operates in the open winding structure; and when the neutral points of the two three-phase windings on the first stator and the second stator are connected, the motor operates in the dual-three-phase structure. 
     
     
       10. The variable-condition driving control system of the multi-excitation-source poles-partitioned dual-stator axial-flux controllable permanent-magnet motor according to  claim 8 , wherein the first field winding and the second field winding are controlled separately through one of the H-bridges; on-off of four switch transistors is controllable to control application of forward and backward excitation currents, thereby achieving magnetization and demagnetization of a magnetic field of the motor; and when the field windings fail, a control effect of a power converter of the armature windings is not affected.